The present disclosure relates in general to the field of tomographic detection methods and signal reconstructions methods, as well as to related detection systems. In particular, it is directed to methods that coherently combine detection signals thanks to beamforming weights judiciously adapted to the context of tomography, to obtain signals focusing on points of interest.
Focused beamformers have been extensively used in phased-array signal processing, leading to simple and efficient imaging procedures, with high sensitivity and resolution. Such beamformers coherently combine networks of antennas to achieve a radiation pattern, also called array beamshape, with high directivity. This beamshape acts as a Dirac-like spatial filter, which makes it possible to scan the incoming signal for particular locations. This imaging procedure is called imaging by beamforming (or B-scan) and is used in several applications of phased-array signal processing, which include radio astronomy, ultrasound imaging, sonars and radars, wireless networks and sound localization. Phased-array signal processing is, so far, exclusively concerned with the estimation of wavefields (acoustic or electro-magnetic).
Besides, tomographic detection systems such as positron emission tomography (PET) are known, which provide medical imagery techniques that are notably used to observe metabolic processes in the human body (e.g., it allows the metabolic activity of an organ to be reconstructed). PET scanners comprise a number of scintillation detectors arranged in a ring structure, which detectors sense annihilation photons produced from the positron emission decay of a radioactive tracer injected into a living subject. Various 2D or 3D reconstruction techniques have been proposed. Yet, PET imaging methods mostly rely on the so-called filtered back projection (FBP) methods.